DESCRIPTION. 125 



usually darker than the rest. Lateral teeth elon- 

 gated, inserted; primary ones small. 

 Inhabits the British coast. 



Fig. 5. Hinge of Cardium echinatum. 



Fig. 6. Cardium edule. 



Shell antiquated, with 20 — 30 rounded ribs^ ob- 

 soletely imbricate. 



Lister Conch, t. 333. f. 170. t. 334. f. 171. 



Specimen pale brown, cinereous towards the 

 margin ; a dark brown and tawny spot upon the 

 internal cavity of the anterior slope. 



This shell, which is the common cockle of the 

 market, is found in great numbers on the British 

 coast, buried in the sand at no great distance from 

 the surface. 



Fig. 7. C. Cardissa. 



Shell cordate, valves compressed, dentato-cari- 

 nate ; beaks approximate. 



Lister Conch, tab. 318. 



Specimen white; equivalve; ribs oblique; beaks 

 slightly crossing each other; cordate impression 



